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This work examines the performance of reinforced concrete (RC) beams strengthened using bonded steel wire rope (SWR) at various prestressing levels. The strengthening approach has, however, been applied to the flexural strengthening of RC T-beams in the negative moment region, in order to determine its advantages. For this purpose, four RC T-beams were fabricated and tested under monotonic four-point bending: one control beam (S00), one beam strengthened with non-prestressed SWR (S20), and two beams strengthened with SWR (prestressed at 10% and 20% of their ultimate tensile strength: S21 and S22). The results indicate that the strengthened beams exhibit higher load-carrying capacities. Specifically, the cracking load, yield load, and ultimate load of S20, S21, and S22 increase by 10%–30%, 30%–50%, and 50%–90%, respectively, compared to S00. Additionally, there is an improvement in stiffness and energy absorption capacity. However, these strategies may have a dual effect on the specimens, resulting in a reduction in their ductility index. Finally, the tested beams were replicated using a three-dimensional finite element model, which has proved effective in predicting the behavior of such structures and, therefore, was found to be appropriate for use in future studies. [ABSTRACT FROM AUTHOR]

The use of carbon fiber-reinforced polymer (CFRP) rods offers a good solution for external strengthening of flexural reinforced concrete (RC) members. Limited data are available on the behavior of beams externally reinforced with CFRP rods under a loading–unloading protocol, which is of great importance for structural components subjected to vehicle loading. The embedment depth mandated by the majority of standards cannot always be acquired due to concrete cover limitations; the influence of embedment depth under this loading–unloading sequence needs to be investigated. This research studied the effects of rod embedment depth by comparing fully-embedded rods with half-embedded rods under a loading–unloading protocol and comparing the results with monotonic responses. An identical specimen without CFRP reinforcement functioned as the controlling element. The near-surface mounted technique (NSM) was used to integrate the rods with the concrete. The results show that CFRP rods positively affect the load-carrying capacity under a loading–unloading condition. The rods reduce the member's ductility under monotonic loading but have no negative impact under loading–unloading. Whereas the difference in embedment depth configuration slightly affected the enhancement under monotonic loading, the half-embedded rods drastically reduced the capacity improvement under the loading–unloading sequence. An embedment depth deviating from the advised depth, should not be implemented for members subjected to a loading–unloading condition. The CFRP placement method had an impact on the failure behavior of the elements. The half-embedded rod failed by debonding between the rod and the epoxy resin, while the fully-embedded members were characterized by concrete spalling. [ABSTRACT FROM AUTHOR]

Abstract: Abaqus finite element program is employed to analyze the ultimate load capacities of square reinforced concrete plates strengthened by fiber-reinforced plastics. Appropriate constitutive models are introduced and validated to stimulate nonlinear material behavior of reinforced concrete and fiber-reinforced plastics. The influences of FRP reinforcement, steel reinforcement, and concrete properties on the ultimate strengths of the reinforced concrete plates are investigated. Finally, based on the numerical results, empirical equations are proposed to predict increment of ultimate load capacities of the square reinforced concrete plates strengthened by fiber-reinforced plastics, which would be useful for practical engineering applications. [Copyright &y& Elsevier]

Under cyclic loading circumstances, reinforced concrete (RC) constructions may be subject to failure. Because they may indicate inadequate capacity owing to aging, environmental effects, or unintentional impacts, strengthening is critical to resist static and cyclic loads. Therefore, the goal of this research was to look at how bare and negative moment region strengthened RC T -beams behaved under monotonic and low reversed cyclic loads. As the strengthening system, carbon fiber reinforced polymer (CFRP) rods having different embedment depths were used with a near-surface mounted (NSM) approach. The findings of this study demonstrated that the impact of NSM-CFRP rods was sufficient for extending the ultimate load and capturing cracks under monotonic loading. Additionally, as compared to their bare counterparts, the negative moment region NSM-CFRP strengthened beams showed improved hysteresis behavior, a larger energy dissipation capacity together with initial stiffness, and a reduced damage index under cyclic loading. Moreover, the experimentally determined load-carrying capacities matched reasonably well with the theoretical predictions. [ABSTRACT FROM AUTHOR]